In this paper a method is presented for copyright protection in digital images. Copyright protection is achieved by embedding an invisible signal, known as digital signature or watermark, in the digital image. The met...
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In this paper a method is presented for copyright protection in digital images. Copyright protection is achieved by embedding an invisible signal, known as digital signature or watermark, in the digital image. The method proposed in this paper casts the signature in the frequency domain by slightly modifying the values of randomly selected DC coefficients of the Discrete Cosine Transform (DCT) of the image. The same method is applied also on the Subband or Wavelet Transform coefficients. An adaptive method is proposed also based on perceptual criteria that guarantees the invisibility of the watermark and avoids the deterioration of the image. Signature detection is done via hypothesis testing, without to use any information from the original image. The watermarks embedded by the proposed method are very resistant to JPEG and other frequently used compression. Experimental results using real image data verify the effectiveness of the method.
This paper introduces the use of two new features for speaker identification, Residual Phase Cepstrum Coefficients (RPCC) and Glottal Flow Cepstrum Coefficients (GLFCC), to capture speaker-specific characteristics fro...
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This paper describes the 'LipTelephone' system, which is being developed under a Greek AMEA research project, with the purpose to serve as a videophone that can also be used by lip readers. This system aims to...
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ISBN:
(纸本)1586030639
This paper describes the 'LipTelephone' system, which is being developed under a Greek AMEA research project, with the purpose to serve as a videophone that can also be used by lip readers. This system aims to combine model-based with traditional coding techniques in order to exploit the information redundancy in a scene of known content, while achieving high fidelity representation in the specific area of interest, which is the speaker's mouth. The recent MPEG-4 coding standard provides the framework, which is employed, for these purposes.
A rate-distortion framework is used to define a verv low bit rate coding scheme based on wireframe model adaptation and optimized selection of motion estima tors. This technique achieves maximum reconstructed image qu...
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A rate-distortion framework is used to define a verv low bit rate coding scheme based on wireframe model adaptation and optimized selection of motion estima tors. This technique achieves maximum reconstructed image quality under the constraint ot a target bit rate for the coding of the motion vector field, the wireframe representation information and the prediction error. Ex-perimental results illustrating the performance of the proposed techniques in very low bit rate image sequence coding application areas are presented and evaluated.
This paper presents a comparison of three techniques for dimensionally reduction in feature analysis for automatic speech recognition (ASR). All three approaches estimate a linear transformation that is applied to con...
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In this paper a procedure for visualisation of videocon- ference image sequences using Virtual Reality Modeling Language (VRML) 2.0 is described. First, image sequence analysis is performed in order to estimate the sh...
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In this paper a procedure for visualisation of videocon- ference image sequences using Virtual Reality Modeling Language (VRML) 2.0 is described. First, image sequence analysis is performed in order to estimate the shape and motion parameters of the person talking in front of the camera. For this purpose, we propose the K-Means with connectivity constraint algorithm as a general segmentation algorithm combining information of various types such as colour and motion. The algo-rithm is applied "hierarchically" in the image sequence and it is first used to separate the background from the foreground object and then to further segment the foreground object into the head and shoulders regions. Based on the above information, the 3D shape parameters are estimated for each sequence and a 3D model is automatically adapted. The rigid 3D motion is estimated next for each sub-object. Finally a VRML file is created containing all the above estimated information and can be viewed using any VRML 2.0 compliant browser.
This paper develops a methodology consisting of improved previously known methods and novel techniques for the model based coding of a human face. An image scene is analysed to locate the position of human faces and t...
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In this paper a procedure for visualisation of videoconference image sequences using Virtual Reality Modeling Language (VRML) 2.0 is described. First image sequence analysis is performed in order to estimate the shape...
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The optimization of microelectronic devices and Microelectromechanical Systems (MEMS) technology depends on the knowledge of the mechanical and thermophysical properties of the thin film materials used to fabricate th...
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The optimization of microelectronic devices and Microelectromechanical Systems (MEMS) technology depends on the knowledge of the mechanical and thermophysical properties of the thin film materials used to fabricate them. The thickness, stoichiometry, structure and thermal history can affect the properties of thin films causing their mechanical and thermophysical properties to diverge from bulk values. Moreover, it is known that the mechanical and thermophysical properties of thin films vary considerably at different temperatures. Bulk properties of semiconductors have been characterized over a wide range of temperatures;however there is limited information on thin film properties of silicon-based compounds such as silicon nitride, specially at high temperatures. In our work, MEMS devices designed to record the localized maximum temperature during high temperature thermal processes, which we call Breaking T-MEMS, will be presented as a way to determine some of the mechanical properties (Young's modulus and fracture strength) and thermophysical properties (coefficient of thermal expansion) of silicon-rich nitride thin films at high temperatures. The Breaking T-MEMS device consists of a thin film bridge suspended over a substrate. During testing, the devices are thermally loaded in tension by heating the sample. The low coefficient of thermal expansion of the film relative to that of the substrate causes the thin film bridge to break at a specific temperature. Through a combination of indirect experimental measurements, analytical expressions, numerical and statistical analysis, and if the experiments are conducted using at least two different substrates of known temperature-dependent coefficients of thermal expansion, some of the material properties of the film can be calculated from the breaking temperatures of various devices. The two candidate materials for the substrate are silicon and aluminum oxide (sapphire).
A digital lossless bounded-real (LBR) transfer function, more commonly known as a stable allpass function, maintains the LBR property under multiplier coefficient quantization when implemented by networks that are str...
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A digital lossless bounded-real (LBR) transfer function, more commonly known as a stable allpass function, maintains the LBR property under multiplier coefficient quantization when implemented by networks that are structurally LBR. A systematic method is outlined for generating all possible such realizations for second-order transfer functions containing a minimum number of multipliers and delays, allowing the designer to take advantage of the flexibility offered by a catalog of such realizations. Illustrative examples are included.
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